IF there is a workshop creaking under similar pressure to the one building toys for Father Christmas at the moment, it is Wales’s fabled fly-half factory.

This country’s conveyor belt of No. 10s is vaunted as an unfailing production line of top-class playmakers, churning out players with the robotic efficiency of a vending machine.

Fly-half is, after all, the position which fuels the most heated debate in Wales, and the man in possession of the shirt can expect to be scrutinised more than any other player.

Rhys Priestland would tell you as much. After a sparkling World Cup, the Scarlets man was heralded as the man to wear 10 for Wales for a generation.

But after an indifferent end to the Six Nations and a torrid autumn, the 25-year-old faced a torrent of criticism which drove him to lock himself away in his flat for days and to seek the help of a sports psychiatrist.

He has now been spared what seemed an inescapable pressure, but in a manner in which nobody would have wished for.

Priestland yesterday underwent surgery on an Achilles tendon he ruptured during the Scarlets’ defeat to Exeter last Saturday, ruling him out for the rest of the season.

It is a devastating blow for the 25-year-old, who will now miss next year’s Six Nations and a British & Irish Lions tour. It will also present another player with the chance to take on the often-haunted chalice of being Wales’s fly-half.

Every Welsh-qualified No. 10 will be analysed intently between now and when Wales begin their Six Nations campaign against Ireland.

Above are five candidates who will be hoping to start at the Millennium Stadium on February 2.

DAN BIGGAR

THE man who calls the shots at the Ospreys has had to bide his time for an extended run in the Wales side, but his chance may finally arrive come next year’s Six Nations.

Derided in the past for being a mechanical player who depended too heavily on his kicking game, Biggar has improved his running and passing to make himself a more innovative attacker.

The metronomic accuracy of his boot is still intact too, which would suit Wales’s attempts to dominate matches territorially.

Won an 11th Wales cap against Samoa this autumn, but was denied the time to impress after he was injured in the first half.

Biggar has had to wait in the shadows long enough. The 23-year-old deserves his chance.

JAMES HOOK

JAMES Hook must feel like the schoolboy at the back of the classroom who has had his arm outstretched for ages, desperate to shout out the answer to a long-standing question.

For years, the Perpignan fly-half was championed as the man to restore Welsh rugby’s golden glow, the silky-skilled playmaker who was being compared to the game’s greats before he had even reached his 21st birthday.

He hasn’t regressed as a player. If anything, since moving to France, the former Osprey has evolved into a more complete fly-half, who can orchestrate a back division with real authority.

The Wales coaches seem to disagree, reluctant to pick Hook after a shaky display in the World Cup semi-final loss to France.

MATTHEW MORGAN

ANOTHER precocious playmaker who is deemed too unpredictable by some coaches.

Morgan is an outrageously talented athlete, who was dancing his way past Welsh Premiership defences for Swansea before he had even turned 18.

The Osprey took to Wales Under-20s matches with similar ease, his pace and trickery overwhelming his opponents during the 2011 Six Nations.

But it has not been quite so easy for the 20-year-old at regional level.

Morgan’s kicking has improved and his decision-making is more assured with every game he plays but, with Dan Biggar for company at his region, the pocket rocket has found game-time limited and his progress somewhat stunted.

RHYS PATCHELL

RHYS Patchell was still playing for his secondary school 18 months ago but, having starred for the Blues this season, the 19-year-old has catapulted himself on to the national side’s radar.

The red-haired Cardiff fly-half can also operate as a full-back, and his kicking — both from hand and at goal — has caught the eye in his debut campaign.

A wiry figure of 6ft 3in, Patchell is a languid runner whose slick passing skills bring the centres outside him into play.

Having played only ten games for the Blues, talk of an international call-up may be a little premature. Patchell is still very much a work in progress, and he will need to improve his running game and tackling before a Wales cap beckons.

GAVIN HENSON

WE may have thought the once-golden (yet permanently orange) boy of Welsh rugby may have been consigned to the wilderness for good, but Gavin Henson is still lurking on the periphery.

Now 30 years old, it seemed the former Ospreys utility back saw the passing of his final Wales chance when he suffered an injury during last year’s World Cup warm-up match against England.

Yet still the double Grand Slam winner lingers.

Henson is now at London Welsh and, having played regularly and impressively at fly-half, it would not be beyond the oft-stretched realms of possibility in Welsh rugby for Rob Howley to give Katie Price’s new squeeze a call.